Rotary kiln construction



Feb. .2, 1960 P. L. SCHOONOVER 2,923,538

ROTARY KILN CONSTRUCTION Filed Sept. 19, 1955 3 Sheets-Sheet 1 Jim- 1.

INVENTOR. f P4; I. scx-laauavae,

Feb. 2, 1960 P. 1.. SCHOONOVER 2,923,538

ROTARY KILN CONSTRUCTION Filed Sept. 19, 1955 3 Sheets-Sheet 2 .PflUL L. scHoaa/ovEQ,

INVENTOR.

Feb. 2, 1960 Filed Sept. 19, 1955 5 P. SCHOON OVER ROTARY KILN CONSTRUCTION 5 Sheets-Sheet 3 PQUL 1;- scyoo/vovse,

INVENTOR.

United States Patent ROTARY KILN CONSTRUCTION Paul L. Schoonover, Sherman Oaks, Calif., asignor to Monolith Portland Cement Company, Los Angeles, Calif., a corporation of Nevada The present invention relates to the construction of newand improved rotary kilns. More specifically, the invention relates to apparatus forming a part ofa rotary kiln, which apparatus is used to introduce solid material into the kiln proper. j

Rotary kilns as used in the cement and a largenumber of other industries consists of an elongated cylinder mounted at an angle to the horizontal in such a manner that it can be rotated. During rotation of a cylinder of this type solid material is introduced into the upper end of the cylinder and is conveyed as a result of the rota- .tion to the lower end of the cylinder while being treated within the kiln. Normally such treatment includes contacting the solid material with hot gases which are passed through the kiln inthe opposite direction to the direction of movement of the solid material.

' In the construction and operation of rotary kilnsof this categorythere are a number of problems. Certain of these problems involve introducing finely ground solid material into the kiln proper without causing a part of this material to be picked up by a hot gas stream. Normally these streams have a very high velocity. If any substantial amount of gas turbulance is present where the solid material is introduced into the kiln proper a material amount of the solid material may be lost as dust in the gas stream. On many occasions separate dust collectors have been employed to recover this lost material. 7 An objective of this invention is to provide constructionsfor introducing finely divided solid material into a rotary kiln which substantially do away with problems such as are briefly indicated in the preceding paragraph. A more specific object of the invention is to provide means for introducing solid material into a rotary kiln which serves to constrict the gas flow through the kiln adjacent to these means so as to create a quiescent gas zone next to these'means in order that solidmaterialcan be introduced into this quiescent zone. Thus, by this expedient, loss of solid material 'into the gas stream is substantially eliminated. "Such loss of solid material is, also reduced with ,the

-pr'esent invention by forming the means employed to introduce the solid material into a rotarykiln in such v 'tional rotary sea1s 22 so as to prevent gas leakage, As

amanner that the material introduced into the kiln is deposited during rotation of the kiln upon and adjacent to material already present within the kiln. This feature of depositing material is considered to bequite important since with the prior known structures material is dumped .or conveyed into the kiln proper in such a manner as to cause dust loss. Thishas the effect of-resulting in some .of this material being picked up'by a gas stream and carried from the kiln asdu'st. An object of this invention is to provide means for introducing solid material into a kiln and for depositing such material already'in the kiln so as to avoid undesired dust losses.

5: Other objects ofthis invention are to provide ei ficient, ,;easily-, and comparatively cheaply manufactured structures for carrying out the aforegoing objectives, as well" Patented Feb. 2, .1960

asto provide methods for introducing material into-a rotary kiln as herein described. Still further objects 'of this invention, as well as many advantages of it, will be apparent from the remainder of this specification, including the appended claims and the accompanying drawings in which:

Fig. 1 is a cross sectional view taken generally along line 1-1 of Fig. 2, showing in cross section a rotary kiln of the present invention;

Fig. 2 is a side view of the structure shown in Fig. 1, this view being partially in cross section;

Figs. 3a, 3b and 3c are schematic views explaining the operation of the instant invention;

Fig. 4 is a cross sectional view taken on line 4-4 of Fig. 2;

Fig. 5 is a view taken on line 5-5 of Fig. 4;

. Fig. 6 is a cross sectional view taken on line 6-6 of Fig. 5; and

Fig. 7 is an isometric view illustrating in greater detail the construction of a member formed in accordance with this invention for introducing material into a rotary kiln.

The actual inventive subject matter considered to be present in this specification is defined or summarized in detail by the appended claims. If desired, it may be indicated for purposes of explanation that this invention concerns rotary kilns incorporating a plurality of members for introducing material into these kilns, each of these members having an inlet located on the outside of a kiln, a passage leading from such an inlet into the interior of the kiln, and an outlet connected to sucha passage, this outlet being located within the interior of the kiln. These members are preferably formed of steel or other equivalent material, and are located as hereinafter described.

In Figs. 1 and 2 of the drawings there is shown part of a conventional rotary kiln 10 employing this invention. This kiln 10 includes an elongated cylindrical metal shell 12 located upon conventional means (not shown) so that as the kiln 10 may be rotated in the direction indicated in order to movematerial 14 within the kiln in the direction shown. When the kiln 10 is employed in the cement or other similar industries a refractory brick lining 16 is normally located within the shell 12 so as to prevent. damage from hot gases flowing within the kiln. Such gas flow is normally countercurrent to the movement of the material 14' as shown in the drawings; during the operation of the kiln 10 the material 14 normally is carried within the kiln 10 at the side of thiskiln as shown atwhat is termed an angle of repose. I v H With the preferred embodiment of the invention finely ground solid'material being fed into the kiln 10 is conveyed through a chute 18 into a housing 20 surrounding the kiln 10. The edges of the housing 24) adjacent to this kiln are sealed with respect to the kiln by convenangles to the axis of the kiln 10; they are attached to the shell12 by rivets 27 or other'equivalent means. The flanges 24 serve to 'aid in directing the material from the chute 18 into the members '26, and hence may be termed guide means. If desired, these flanges 24 can beformed as projections on the members 26. 1 1 These members 26 canbe termed scoopsyvsincefihey are provided with inlets 28 located on the outside of the 2,923,538 I d H kiln between the flanges 24 substantially facing the direction of rotation of the kiln so as to pick up material from the chute 18 as the kiln 10 is rotated. The actual construction of the members 26 is best seen .in Figs. 4, 5, 6 and 7 of the drawings. Here it is shown that the inlet 28. for any one. of theimembers 2.6, is connected; to a curvedconduit, passage or conveyor section 30 leadi g to? the interior of the kilnlti. The preferred shape of the section 3i as shoizvnv in the drawing, serves to prevent a back flow. Each of the curved conduits 3t]v includes one part 30a located on the exterior of the kiln shell 12, another part 30b extending in a radial manner through the kiln shell 12, and another part 30c curving away from thetransverse plane of the members. 26.,within the interior of the kiln shell. 12 so as to. extend parallel to the axis of the kiinishell toward the lower end of the kiln. In the interior of the kiln-each of the members 26 is provided with an outlet 32 from the partfillc .ofthe conduit 30 substantially facing the lower end of the kiln in the direction of material movement through the kiln.

Each outlet 32 is. located between the kilnshell 12 and the portion of the Wall of theconduit 30 extending closest to the axis of the kiln. x

As is best seen in Fig. 1 of the drawings, all of the outlets 32 project into the interior of the kiln past the brick lining 16 so as to define What amounts to a ringor restricted orifice for the passage of gas within the kiln. This ring or orifice is quite important to one. aspect of or the shape of the passages 3i) maybe altered. Thus, it is also possible to form the passages 3tlso that they are substantially straight and still retain some of the advantages of the invention, although this is not preferred because kilns havingsuch passages will not operate as well as kilns in which the members 26am of the con figuration indicated inthedrawings, All such modifica tions are to be considered as part of the present invention insofar as theyaredefined by the appendedclaims. Al: though extensive reference has been made in this specification to the use of this invention in the cement industry, it is considered obvious that it canhe employed; with rotary kilns usedfor any, purpose.

Iclaim:

- kiln shell rotatably mounted at an angle tothe horithe operation ofthe invention because, while of an essentially non-continuous segmental construction, it serves to cause the gas flow within the kiln 1% adjacent to the members 26 to constrict in diameter, resulting in a substantially'quiescent'gas zone surrounding the outlets 32. If desired, bricks or other material can be spaced Within the kiln 10 between the members 26 so as to make this ring or orifice substantially continuous, but this is not considerednecessary in order'to obtain the advantages of this invention. a

The members 26 are curved in such. a manner that when the kiln it) rotates material from the chute 18 goes into the inlets 28 and thence through the passages 30 and through'the outlets 32'. The inlets 28 are so formed as to generally face the direction of rotation of the kiln 10, while the outlets 32 are positioned at anangle to the inlets 28 so that material entering the kilnis conveyed towards the sides of the members 26 facing the direction of material travel within the kiln. Furthen these'outlets are so located that when material passes through them this material is deposited in the quiescent zone referred to above.

In Figs. 3a, 3b and 3c the manner in which the members 26 operate is diagrammatically illustrated. As the kiln 10 turns a member 26 first dips into any material which may be in the housing 20 so as to'pick up part of this, material, and then, if not full, receives further material from the chute 18. Because of the shape of the passage 30 such material is not conveyed directly into the kiln 10, but only moves into the kiln during rotation so that this material is deposited through the outlet 32 upon the material 14, as the member passes the material in the kiln and the angle of repose referred to earlier.

In e sence, a ember 2.6 P lls a ay f om th ma e i Passin t r he out e inst d f c c n s ch aterial within the kiln. It is considered obvious that this does not involve any; substantial amount of turbulence, and hence substantially no material is picked up by the gas flo ng through the t is impor ntfie ha a sufiicient number of these members 26 so that the flow of material into the kiln issubstantially continuous.-

Those skilled in the art to which this invention pertains will realize that a number of modifications may bemade without departing from the essential features of the invention. As an example of such modification, the inlets 28 may extend as indicated by the dotted lines in'Fig. 5,

zontal so as to have an upper end and a lower end, said kiln shell beingmounted so as to'be capable of being rotated in a given direction aboutits axisso as to cause material within said kiln shell to move toward the lower end of said kiln shell while gas flows from one end of said kiln shell to the other end of said kiln. shell, the improvement which comprises: "a plurality of members for introducing materialfinto the interior of said kiln shellfrom the exterior, thereof, said members being located in a plane'at aright-angle to the axis;

of said kiln shell, ea'chof said members including a curved c'onduit,fone part ,of whichis located on the exterior of said kiln shellin said plane, another part of which extends in a radial manner through said ikiln shell into the interior. thereof, and another part of which curves away fromsaid plane within the interior of said kiln shell so as to extend parallel to the axis of said kiln shell towardsaid lowerend of said kiln shell, said members each includingan inlet to the conduit on such member, said inlets facing in saiddirection of rotation and being located on the exterior of said kiln shell within said. plane, and each of said members including an outlet from the third-mentioned part of said conduit, said outlets facing saidlower end of said kiln upper end of said kiln shell from said outlets, said orifice extending substantially around theinterior of said kiln shell and serving to constrict the flow ofgas moving through said kiln 'so as to cause the formation of a quiescentgas 'zone adjacent; to said outlets, whereby as said kiln is rotated in said given direction, material is moved from said inlets through said conduit parts and t u h a dq and is d p si ed nia quiecent gas zone created by said orifice restricting the w of gas t r h s i ns e lt i 2. In a rotary kiln as defined 1 apair of pa al el flanges o atcd' n l nr a g t an l s. o the h l n t e e e io he eof at e. sides, of. the parts of said members located on the exterioroi said References Cited the file of patent l d 1. In a rotarykiln. hayingan elongated, cylindrical of said kiln, said flanges being secur d to said,

met:- 

